RobertI

It was extremely windy, well done for venturing out. Might not be perfect, but one for the scrapbook!

Astounding. Galaxies abound like water fleas in a pond. When I have some time I'd like to compare the map to the image in more detail.

5 hours ago, DanyalAG said:

Just one question; are cooling fans required for a 6 inch Newtonian?

I've always read that 6" scopes cool down in around 20-30 minutes, while bigger aperture (8" and up) take longer to cool down, and so a cooling fan is necessary for them.

Or am I missing something here?

A fair question. I bought the scope specifically for double star and planetary observing and from my research it seems that a fan can improve a newtonian's  ability to resolve close doubles and fine planetary detail by removing the 'boundary layer' of warm air above the mirror. Apparently this boundary layer is always present to a greater or lesser extent, even if the mirror has cooled, and even on smaller scopes. The fan at low speed creates a gentle current of air up the tube which keeps the air moving over the mirror and removes the boundary layer problem. I've read it works well, but I have not had a chance to test it the difference with the fan on and off under different conditions.

Thanks Ed!

On a windy night with surprisingly steady skies, I chose my smallest scope to dart between the gusts. With my Williams Optics Zentithstar 66 mounted on a Giro-WR atop a Horizon tripod I ventured forth for a short session.

Starting with Izar in Bootes, the star showed a lovely but slightly broken diffraction pattern. However no sign of its smaller companion even at the highest mag I could manage of x78, not even an elongation. No matter, perhaps a bit too challenging for this tiny scope and these lowish magnifications, so on to Pi Bootes. This was a lovely double of white stars of slightly unequal magnitude separated by 5.4" - an easy split. Next on to Xi Bootes, another pair separated by a similar distance to Pi, but with a brighter primary and fainter companion. 39 Bootes was much closer at 2.6", and I didn't expect to see anything given my failure with Izar, but surprisingly it was immediately obvious and between gusts I could fleetingly see a gap. Skysafari said the pair had a magnitude difference in brightness but to me they looked almost identical. 

Now my eye was 'in', I thought I'd have another go at Izar. Same result as last time, but this time I noticed a brightening of the diffraction ring in one area. Checking the positional angle it seemed to be in the right position for the companion. So I think definitely more power needed and possibly aperture....and possibly better seeing!

I was getting really cold by this point, so thought I'd finish with some DSOs. M13 rising above the rooftops. I was expecting nothing but a blur with this aperture, but was amazed that, with averted vision, I could make out numerous stars on the periphery and could clearly see it was an object made up of thousands of stars rather than a faint haze.

Finally a scan around the bowl of Virgo with the zoom eyepiece. I found two bright galaxies in the same FOV, I believe they were M59 and M60 but not confirmed. It was intesting to zoom in and out; at lowest power, with the brightest skies, the galaxies disappeared completely in the murk, but zooming in the skies became darker and the galaxies more and more evident. There were a number of other galaxies in the area but I was just too cold to try and identify them by this point. Time to pack away.

I have been looking to get a higher power eyepiece to use with this scope anyway, so Izar will be my first target when I do!

Nice report Martin, some interesting objects. Also interesting to see the limiting magnitude in play, stopping you seeing q3 by just 0.6 mag. An interesting field to have a go at when I'm next out. Almost tried my first EAA session in a long time last night, but just too windy, so ended up with visual again!

Nicely done.

Sorry to keep quizzing you, I have a friend who is a relative noob, they currently have a very simple Celestron Travelscope 70 and want to upgrade and this setup seems ideal. I like the idea of the Az-Gti as, if they the find the goto a bit complicated at first, or just can’t be bothered with power, they can still use it manually (unlike the Celestron mounts). Do you think this is a good beginner setup? How easy do you find the app for aligning and finding stuff?

Thanks for reply, sound like a good combination of scope and mount. Am I right in thinking it is ‘freedom find’ so you can move the scope manually and still retain the alignment?

Nice report, looks like you have a good one there. How did you find the stability of the whole setup? Did you feel the AzGti mount head was man enough for the C6? What about the tripod - seems to be the weak link? 

On 05/03/2020 at 21:22, HWStar said:

The sensor is 1.3 meg, which is old tech by today's standards, I think (what do you think?)

Personally I think 1.3 meg resolution is perfectly adequate for this kind of application and will be for years to come. I use a Lodestar for my EAA which is a mere 0.43 meg and it produces some pretty satisfying results (albiet black and white) - not mind blowing, but way more than eyeballing through a scope. Just my two cents.

6 hours ago, CraigT82 said:

Edit:  just thought... If the frac is of a much longer f ratio than the reflectors, the depth of focus will be greater and the wavefront disturbances caused by turbulent seeing would be less visible at the eyepiece?

I read an article recently (with some pretty in depth analysis which I didn’t understand) which concluded that for a given aperture, the focal ratio makes no difference to how it is affected by seeing. It was primarily about aperture. I need to see if I can find the article now! 
 

Edit: Found the article https://www.fpi-protostar.com/bgreer/seeing.htm

Re-reading the article, it actually says that longer focal ratio scopes might sometimes perform better in poor seeing than their shorter focal ratio counterparts, but not because of increased depth of focus. 

Amazing image Chris that’s a lot of stars!

That is a weird looking object! Thanks for the detailed references, very interesting. 

Great result Chris, you must be dead chuffed with the result. Can you post the final image?

Well done for grabbing the opportunity, that actually looks like a nice observing site. I forget that you don’t have to wait until it’s dark to observe the moon! 

Thanks for the comments @Lockie, @domstar and @Stu  I was really surprised that the galaxies popped out so well as the skies didn’t seem that dark, both naked eye and through the eyepiece, but transparency must have been pretty good somehow. It did make me realise what a difference a really dark sky could make to viewing galaxy detail. I didn’t realise the ngc3628 was the hamburger - do you think that the dark line could be visible in a 6” Newt under my skies? 

Another gusty night, but transparent with moderately dark skies. I cooled the 150P with my newly installed fan on full blast for an hour, then turned it down to minimum speed and began the festvities at 10pm. Seeing was pretty bad as usual, but by the time I finished at 1am, had improved a lot.

Bit of a mix tonight starting with some doubles:

• Iota Cancri - a beautiful double, the 'Winter Alberio' with yellow primary and blue/grey secondary.
• Zeta Cancri  (Tegmine) - A triple with splits of 6" and 1.1". Recently discussed in another thread so thought I would have a go and was pleasantly surprised to be able to split the close pair quite easily at x240, despite the bad seeing, although there were moments when the gap was not clearly visible.

  A couple of carbon stars:

• X Cancri, a lovely rusty orange colour.
• 'La Superba' in Canes Venatici, a beautiful deep fiery orange.

Although the sky seemed quite bright, I thought I'd try some galaxies, and was very pleasantly surprised. Mostly observed at 57x:

• A triplet of M65, M66 and NGC3628 in Leo all visible in the FOV - a thrilling sight. M65 and M66 both pointing in the same direction and very easily seen with bright cores. NGC3628 much fainter, long and thin with not much of a core.
• NGC6307 and 3608 lay nearby,  both fainter and without any discernable shape or bright core.
• M51 in Ursa Major was very bright, with two bright nuclei and extensive nebulosity apparent.
• Over to the more challenging M101, but suprisingly easily found, a large but faint pale diffuse disc.
• Finally M64 the Blackeye Galaxy. Very bright and compact, I really wasn't sure whether the black eye should be visible in a small scope, and I really tried, but with no luck. I upped the magnification to 120x to darken the sky, and the galaxy was more apparent, but I really couldn't see a black mark. By this point I was also using an observing hood and eyepatch! 😄

Overall a nice session and I was very pleased with the scope's performance on galaxies.

As for the fan, I did try comparing views of Tegmine with the fan on and off, but could not see a difference. I suspect this may be of more use on planetary and lunar, or under different conditions (perhaps less windy).  

No sketches tonight, too windy!

It does look intriguing. More than likely a plane or satellite. If you can remember the exact time, you can probably use Sky Safari or similar to eliminate or confirm whether it was a satellite. Could also be a plane at an angle - there is a very famous 'UFO' video which is actually a plane showing this effect.

Great resource Mike, a project for next year as Orion has disappeared behind my house now (I can't really see much of the Western sky). VV790 looks interesting.

Thanks Stu, I can see now that I should ignore the description in SS and go by the orbital view. 👍

Nice session Stu, what a lovely setup too. Tegmine is also on my list of doubles for the next session, the tighter of the pair looks pretty close, but I’m having trouble getting an accurate figure from my resources; SkySafari says 0.8” as of 2005 but widening, another source says 1.0” as of 2008 but widening, so I am assuming it must be between around 1.2” ish and 1.4” ish by now?

Edit: after a bit more rooting around, seems like it’s reached a maximum separation of around 1.1”,so that’s a good split to have bagged. 

Just fitted a home-made cooling fan to the back of the scope using instructions from a fellow SGL member. I didn't do a fantastic job (missing some vital tools), but it does blow a nice breeze up the tube, has a variable speed and is vibration free. My hope is that it speeds up cool down time, but more importantly improves high powered views of lunar, planets and possibly doubles, by removing the boundary layer of warm air that sits over the mirror. It's clear outside but I have a streaming cold so will wait for another time to test it.

Nice session Mike,  the Whale and Cocoon are two of my favourites, particularly the latter with its knots and curves. Nicely captured galaxy group too.

Well done for being brave enough to share this Chris, why shouldn't we share the failures as well as the successes, perfection can get boring (not that I would know!).